Slack adjuster



May 27, 1924. 1,495,438l

J. E. REDFORD SLACK ADJUSTER Fled'March 27. 1923 l l I A'Illlllllillllllillllll` INVENTOR JHN E. REDF'Q F D ATTORNEY JOHN E. BEDFORD, OF KINLOCH PARK, MISSOURI, SSIS-NOR T0y THE AMIIEIIRJKIJAI-Tr` BRAKE COMPANY, OF ST. LOUIS, MISSOURI, 4A CORPORATION O'F MISSOURI.

sLAcK ADJUsTEn. y

ing-rod is employed yand a dog is provided for holding the operating rod-in its adjusted erated to take up slack.

In some instances, it has been found that dueto excessive vibrations of the parts, lthe operating rod tends to gradually slip fory `ward through the dog,so that what might lbe called Jfalse slack is registered.

The principal object of my invention is to provide means in-a slack adjuster of the above type for preventing false vforward movement lof the operating rod.

In the accompanying drawing; Fig. 1 is an elevational view, partly in section, of a slack adjuster embodying my invention; Fig. 2 a plan-:view thereofpartlyin section; and Fig.4v 3y an elevational view-of a portion of the construction shownin Fig. 1, i showing the parts innormal operating position.`

In order to illustrate one applicationof my invention, I have shown my invention applied inl connection with a mechanically operated slack adjuster ofthe type shownv in my prior Patent No. 1,381, 932, dated Juney In'this4 type of slack adjuster,vr the slack Y adjuster isassociated with` the bottom rod member of the ',brakerigging and comprises a sleeve member 1,-,pivotally connected to the end of one brake lever 2, and a rod memposition after they slack-adjuster has opber 3, pivotally connected to the end of theA other brake lever 4, and extending into thel v Appneation mea March 27, 1923. fserizn N6. 627,999.

l either nut vis free to rotatethe rod member 3 maybe moved longitudinallywith respect to thefnut. l j i They adjacent `meeting `faces o-f'the nuts 7 and `8, are yprovided withk cooperating teeth 9 which when engaged are adapted to prevent relative rotative movementl of the nuts and 8 in one directionbut whichfpermit relative rotative movement in the opposite direction. The nut 8` is prevented from moving ,longitudinallyl toward the left by engagement with alshoulder 10 'of the sleeve member 1 and is prevented Jfrom movinglongitudinally towardfthe right by the engagement of a collar `11 lwith a `iiange`12 carried by the sleeve member l1. l f

Theright hand nut 47 may move longitudinally toward the rightagainst` the resist/ ance of a coil spring 13 lni'tlis prevented from moving longitudinally toward the left by lengagement of a 4flange 14 .in 'a groove 15 of the nut. i i

Positionedinparallel alinement with the members 1 and Sis an operating rod 16 having a crosshead 17 secured at the right hand end. SaidA crosshead is providedwith an elongated slot 18 for receiving the extended end of the pin 19 which pivotally connects the v,brake lever 4 with the rod member 3. The crosshead 17 is also providedrwith a slot 20for receiving a pin v21 carried by the brake lever 4. I

The operating rod 16l extends through` openings in an extended portion of` the sleeve member 1 and mounted on said rod is a` tiltable dog 22 subject to .the pressure of a coil spring 23 and having the outer edge in engagement with a flange 24 carried by the sleevey member 1, sothat' the flange 24 acts as, fulcrum for the dog 22 and thereby causes a 'gripping action of the dog on the rod 16, so-"that longitudinal movement of the rod ltoward the left is prevented.

In' addition tothe abovedescribed parts and in accordance withtmy'1 resent inven- 100 tion"a second. t'iltabledog 25 1s mounted on the rod 16 and is subject tothe pressure of a lcoil spring`26;y Mounted on` thev rod 16 is a housing 27', subjecttothe pressure of a coil spring 28 and having a` lange 29 105 adapted to engage the outer edge of the dog 25, so that the flange 29 acts as a fulcrum for the dog 25V and thereby causes a ipping1 action of the dog 265 on the ro 16, so t at forward longitudinal movement of the rod 16 relative to the dog 25 isfprevented. The longitudinal movement of the housing 27 is limited in one direction by engagement with a lug 30 carriedby the sleeve member 1 and by engagement with a lug 31.

1n operation, when the brakes are applied, the brake levers 2 and 4L move so that the pin 21 travels toward the adjusting screw 32 and if the slack does not exceed a prede-- termined amount, as measured by the gap X between the pin 21 and the end of the screw 32, then no slack adjusting action will take place, but if the movement of the brake levers to bring the brake shoes against t-he car wheelsexceeds a predetermined amount, due to wear of the brake shoes, then the pin 21 will act on thescrew 32 vso as to move the crossliead 17 `to the right and thus pull the operating rod 16 forward and through the dog 22 against they frictional resistance of the dog 22 as caused by 'spring 23.

As the operating :rod 16 moves toward the right, the housing 27 is carried forward, compressing the spring 28, by reason of the engagement of the dog y25 with they rod 16. Then theA housing 27 has moved `forward a distance Y, as shown in Fig, 1, the dog 25 will engage ythe lug 31 and thus trip the dog 25, so that further longitudinal movement of the rod 16 toward the right is permitted by the slipping of the rod 16 through the dog 25. I Y

The parts will 'now be' in the normal operating condition. with the dog 25 engaging the lug 3 1, as shown in Fig.v 3.

Upon releasing the brakes, the dog 22 grips the rod 16 and prevents movement of the rod toward the left and as the brake lever 4 moves inwardly in its release 'movement, the pin 21 engages the wall 33 of crosshead 17 which acts as a fulcrum for the pin 21, so that further movement of the brake lever 4 Causes a forward movement to the right 'of the rod member 3. This movement is permitted due to the fact that when force is applied to the rod member 3 in a. direction tending toshift the rod toward'the right, the 'tefeth 9r will disengage to permit a relative rotative movement of the nuts 7 and 8 in oppositie directions, so that longitudinal forward movement of the member 3 is permitted and the bottom rod connection is thus lengthened to compensate for slack.

vlith Athe parts positioned as shown in Fig. f3, the spring, 28 vunder compression and eXert's its force through the dog 25 on the rod 1,6 in fa direction 4tending to hold the 1"odl`1`6` against forward movement to the right, so that when the parts are subjected Leashes to vibration in the running of the car, the device will tend to prevent accidental torward movement of the rod 16 when not intended. The construction will not prevent forward movement of the rod 16, however, when such movement is positively effected by the action of the slack adjuster parts, since in `such case, the forward pull on the operating rod 16, when the pin 21 acts on the screw 32, operates torelease the dog 25, by the engagement of the dog with the lug 31. At the same time, it will be noted that the tension of the rspring 28 is constantly maintained at a fixed point.V

Having now described my invention, what 1 claim as new and desire to secure by Letters Patent, is

1. The combination with a slack adjuster including an operating rod longitudinallyv movable in one direction in the operation of taking up slack anda clutch device for preventing longitudinal movement of the rod in the opposite direction, vof a springl mounted on said rod and adapted to yieldingly oppose longitudinal movement of the rod in the first mentioned direction. y

2. The combination with aslack adjuster mechanism including an operating rod having al forward longitudinal movement in the operation of taking up slack and a dog for preventing rearward longitudinal movement ot said rod, of a spring carried by said rod andoperative to yieldingly oppose forward longitudinal movement of said rod.

3. The combination with a slack adjuster mechanism including an operating rod having a forward longitudinal movement in the operation of taking up slack and a dog for preventing rearward longitudinal movement of said rod, of a spring 'for resisting forward longitudinal movement of said rod, a dog engaging said rod for holding said spring under tension, and means for releasing said dog from said rod upon a forward longitudinal movement of said rod. p

4e. The combination kwith a slack adjuster mechanism including an operating rod having a forward longitudinal movement in the operation of taking up slack and a dog -for preventing rearward longitudinal movement of said rod, of asprin'g for resisting forward` longitudinal movement of said rod, and means for maintaining said spring under a substantially lconstant, tension, regardless of the forward movement of said operating rod. I

In testimony whereof have hereunto set my hand. i

:JOHN E. BEDFORD.

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